Line scan cameras have been implemented in numerous industrial and commercial settings, such as on high-speed mail sorting systems. In one exemplary implementation, a line scan camera may be fixed in a stationary position and mail items may be conveyed to a viewing station within the camera's field of view via a conveyor path. As the mail items reach the viewing station, they may be scanned or photographed by the camera. Image data captured by the camera may be decoded or otherwise processed by a signal processing circuit.
Often, line scan cameras are implemented on mail sorting systems as part of a camera assembly. For example, many line scan cameras reside in a housing which protects the camera's components from the operating environment. The camera assembly may, for example, define an aperture which provides the camera with a field of view toward mail items on the conveyor path. In addition, because many line scan cameras require a mail item to be illuminated with relatively bright light to capture an accurate image, the camera assembly may include lighting components, such as fluorescent, halogen or sodium vapor lamps, to illuminate an item in the viewing station. Further, many camera assemblies include components to aerate and/or cool the assembly, since lighting and/or image capture components may produce sufficient heat to reduce the useful life of other components inside the housing.
Some conventional line scan cameras employ a charge-coupled device (CCD), which is a device comprising an array of photosensitive elements that produces image data in the form of an array of pixels. The CCD typically provides this image data to a signal processing circuit for decoding and processing. The signal processing circuit may reside in a computer external to the camera assembly.